// 进程管理服务实现

use log::info;
use crate::core::{Service, ServiceStatus};

/// 进程管理服务
pub struct ProcessService {
    status: ServiceStatus,
}

impl ProcessService {
    pub fn new() -> Result<Self, String> {
        Ok(ProcessService {
            status: ServiceStatus::Stopped,
        })
    }

    /// 创建新进程
    pub fn create_process(&self, executable_path: &str) -> Result<ProcessId, String> {
        info!("Creating process: {}", executable_path);
        // 这里实现进程创建逻辑
        Ok(ProcessId::new())
    }

    /// 终止进程
    pub fn terminate_process(&self, pid: ProcessId) -> Result<(), String> {
        info!("Terminating process: {}", pid);
        // 这里实现进程终止逻辑
        Ok(())
    }

    /// 获取进程信息
    pub fn get_process_info(&self, _pid: ProcessId) -> Result<ProcessInfo, String> {
        // 这里实现获取进程信息逻辑
        Ok(ProcessInfo::default())
    }

    /// 列出所有进程
    pub fn list_processes(&self) -> Result<Vec<ProcessInfo>, String> {
        // 这里实现列出进程逻辑
        Ok(Vec::new())
    }
}

impl Service for ProcessService {
    fn name(&self) -> &'static str {
        "process"
    }

    fn start(&mut self) -> Result<(), String> {
        info!("Starting Process Service");
        self.status = ServiceStatus::Starting;
        
        // 这里可以添加进程服务启动逻辑
        // 例如：初始化进程表、设置调度器等
        
        self.status = ServiceStatus::Running;
        info!("Process Service started successfully");
        Ok(())
    }

    fn stop(&mut self) -> Result<(), String> {
        info!("Stopping Process Service");
        self.status = ServiceStatus::Stopping;
        
        // 这里可以添加进程服务停止逻辑
        // 例如：终止所有进程、清理资源等
        
        self.status = ServiceStatus::Stopped;
        info!("Process Service stopped successfully");
        Ok(())
    }

    fn status(&self) -> ServiceStatus {
        self.status.clone()
    }
}

/// 进程ID
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub struct ProcessId(u64);

impl ProcessId {
    pub fn new() -> Self {
        static NEXT_ID: std::sync::atomic::AtomicU64 = std::sync::atomic::AtomicU64::new(1);
        ProcessId(NEXT_ID.fetch_add(1, std::sync::atomic::Ordering::Relaxed))
    }
}

impl std::fmt::Display for ProcessId {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.0)
    }
}

/// 进程信息
#[derive(Debug, Clone)]
pub struct ProcessInfo {
    pub pid: ProcessId,
    pub name: String,
    pub state: ProcessState,
    pub memory_usage: u64,
    pub cpu_usage: f32,
    pub start_time: std::time::SystemTime,
}

impl Default for ProcessInfo {
    fn default() -> Self {
        ProcessInfo {
            pid: ProcessId::new(),
            name: "unknown".to_string(),
            state: ProcessState::Running,
            memory_usage: 0,
            cpu_usage: 0.0,
            start_time: std::time::SystemTime::now(),
        }
    }
}

/// 进程状态
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum ProcessState {
    Running,
    Sleeping,
    Stopped,
    Zombie,
    Dead,
}

/// 进程调度器
pub struct ProcessScheduler {
    processes: Vec<ProcessInfo>,
    current_pid: Option<ProcessId>,
}

impl ProcessScheduler {
    pub fn new() -> Self {
        ProcessScheduler {
            processes: Vec::new(),
            current_pid: None,
        }
    }

    pub fn schedule_next(&mut self) -> Option<ProcessId> {
        // 简单的轮询调度算法
        if self.processes.is_empty() {
            return None;
        }

        let next_index = if let Some(current) = self.current_pid {
            let current_index = self.processes.iter().position(|p| p.pid == current).unwrap_or(0);
            (current_index + 1) % self.processes.len()
        } else {
            0
        };

        self.current_pid = Some(self.processes[next_index].pid);
        self.current_pid
    }

    pub fn add_process(&mut self, process: ProcessInfo) {
        self.processes.push(process);
    }

    pub fn remove_process(&mut self, pid: ProcessId) -> bool {
        if let Some(index) = self.processes.iter().position(|p| p.pid == pid) {
            self.processes.remove(index);
            true
        } else {
            false
        }
    }
}